O n Sunday mornings, the small metal cartridges littering the ground behind the residential quads are the only evidence left by the weekend's whippets users. Usually consumed by small groups of students, nitrous oxide-the colorless, sweet-tasting laughing gas stored in the whippet cartridges-is used by transferring the gas to a balloon and then inhaling to achieve a buzz that one Trinity sophomore described as "an up thing, not a chill thing."

Whippets, named for their intended use of propelling whipped cream from its dispenser, have a solid but not dominating presence in the University's social scene.

"It's an easy thing to try, and it seems pretty harmless," the Trinity sophomore said, noting that she encountered whippets at a fraternity function during the first three weeks of her freshman year. "About half my friends have done it or do it."

Jeanine Atkinson, the substance abuse specialist for Student Health Services, said she could not identify when the inhalant first became popular at the University; now, she said, "small pockets" of students use the drug fairly regularly.

The perception that whippets are "pretty harmless" stems partially from the fact that they are accessible, Atkinson said. Nitrous oxide is available at grocery stores and through mail-order catalogs because of its legitimate purposes. Several students said they encountered whippets in high school and found the gas easily available at Duke. They identified Railroad Video, the adult video store on LaSalle Street, as the most popular local vendor of the drug.

Although many students pinpointed brain damage as the main danger of using the gas, Dr. Scott Swartzwelder, co-author of the book Buzzed-which takes a scientific perspective to look at recreational drugs-said this effect is actually associated with other more dangerous inhalants, particularly solvents.

"It's not as clear that [whippets] produce direct brain damage," said Swartzwelder, clinical professor of psychology and behavioral science at Duke. "The danger of whippets is that the effects are pretty powerful and fast."

In Buzzed, Swartzwelder and his two co-authors, also Duke doctors and professors, identified three primary dangers associated with inhaling nitrous oxide: lack of oxygen, physical harm by having the gas-delivery mechanism malfunction or a vitamin B-12 deficiency after repeated use. But the authors noted that nitrous is, in the realm of drugs, relatively low-risk and non-addictive.

The buzz, several users said, is "hard to describe," with lightheaded dizziness resulting from decreased oxygen flow to the brain. They also described distorted and amplified sound and an overall "happy" feeling of being in a separate world; one student described the experience as "pulsing." But the buzz from whippets is short: a "quick high, quick crash," Atkinson said, which lasts 30 to 45 seconds.

Because the buzz is so fleeting, whippets can be pricey. Derek Latta, an employee at Railroad Video, said a box of 24 nitrous cartridges costs $19.99. A "cracker," which is used to puncture the two-inch-long silver metal cartridge, also costs $19.99 at the triple-X store. Latta said students are the primary buyers of the cartridges, and that groups often come to the store more than once a week to buy two or three boxes at a time.

Atkinson and several students said whippets are usually done in groups of five or six. The Trinity sophomore explained that the small-group setting was likely a result of the cartridges' cost.

"I know people who have dropped $100 on whippets in a night," she said. "When they buy [whippets], people don't always want to share with a bunch of people."

One recent graduate said that, at a party he held last semester, a group of about 100 students lined up for hits off a tank of nitrous oxide. The student explained that he set up the tank so guests could inhale the gas through a hose attached to the tank's nozzle. "We had people sucking off the tank all night," he said. "People would suck on it and [sink to] the floor."

He added that the gas causes a severe loss of balance. "You don't want to be standing. You usually sit down when you do it."

The risk of falling is only one of the physical dangers associated with inhaling nitrous. As the authors of Buzzed noted, the cold temperature of the gas can damage the mouth, trachea and lungs if the gas is inhaled too quickly. Delaney Steele, Engineering '99, said she knows of students who, in using whippets carelessly, let the balloon slip off the cartridge and burned their fingers.

Steele also said she had witnessed some friends "lose control" of their bodies while using whippets; she described students drooling on themselves and turning purple.

Several students said whippets were used mostly to accompany other drugs-usually alcohol or marijuana.

"It's something else to do while you're [high]. It's easier not to think about hurting yourself, how dangerous it is, when you're [high] on something else," the Trinity graduate said.